ES2978943T3 - Spring compressor - Google Patents

Abstract

The invention relates to a spring compressor with a loading device (3) which can be axially inserted into a helical spring (2) to be loaded and which has first and second loading plates (4, 5) which can be coupled to the loading device (3) at a distance from each other, the second loading plate (5) having an opening (7) for receiving the loading device (3), a pressure piece (10) being movable along the loading device (3) by an actuator to adjust the distance between the loading plates (4, 5), a cap-shaped contact surface (19) for force transmission and an anti-rotation means being formed between the pressure piece (10) and the second loading plate (5) to prevent rotation of the pressure piece (10) relative to the loading plate (5), the anti-rotation means having projections and recesses for the projections (20). The protrusions and pockets interrupt the calotte-shaped contact surface in the circumferential direction and divide it into contact surface regions that are separated from each other, where the calotte-shaped contact surface regions are larger in total in the circumferential direction than the circumferential region in which the protrusions and pockets are arranged. (Automatic translation with Google Translate, no legal value)

Description

DESCRIPTION

Spring compressor

The invention relates to a spring compressor according to the features of claim 1.

EP 1591 207 B1 discloses an internal compressor for tensioning a helical compression spring according to the preamble of claim 1, which has a tensioning drive with a threaded spindle and two tensioning plates which are inserted between the turns of the helical compression spring to be tensioned. The tensioning plates have contact surfaces adapted to the helical compression spring. One of the two tensioning plates has an opening in the edge so that the threaded spindle can reach the tensioning plate from the side.

The other tensioning plate has a central opening with a support surface for a pressure piece. The pressure piece has a spherical cap-shaped surface, so that a certain inclination between the pressure piece and the tensioning plate is possible.

In the mounted position of a suspended chassis, the helical compression springs generally do not run straight, but are slightly bent. The spring coils therefore do not run parallel to each other, with the result that the tensioning plates are not initially parallel to each other during tensioning. The spherical cap shape ensures a certain balance in the area of the two tensioning plates.

EP 1905 545 B1 also discloses a spring compressor for helical compression springs with a spherical-shaped receptacle for a pressure piece on the outside of a tensioning plate. In addition to the receptacle, the tensioning plate has a ring of depressions and projections. Two radially projecting buttress bodies are provided on the pressure piece for engaging in the depressions. The protection against rotation requires additional axial and radial space.

The object of the invention is to create a spring compressor which allows a limited tilting possibility of the tensioning plate with respect to the tensioning apparatus arranged inside and at the same time allows the use of a short-length pressure piece with the most compact possible construction.

This object is carried out with a spring compressor with the features of claim 1.

The spring compressor according to the invention comprises a tensioning device which can be axially inserted into a helical spring to be tensioned. The spring compressor comprises a first and a second tensioning plate. The tensioning plates can be coupled to the tensioning device at a distance from one another. The tensioning device has a drive end, the second tensioning plate being arranged adjacent to the drive end. For this purpose, the second tensioning plate has an opening for receiving the tensioning device. The tensioning device also has a pressure piece which can be moved along the tensioning device under the influence of an actuator to adjust the distance between the tensioning plates. The pressure piece presses axially on the second tensioning plate. The force is transmitted via a cap-shaped contact surface between the pressure piece and the tensioning plate. In addition, a rotation-proof lock is provided between the pressure piece and the second tensioning plate to prevent the pressure piece from rotating against the tensioning plates. The anti-rotation device has projections and pockets for receiving the projections. In the invention, the projections and pockets are located on the cap-shaped contact surface itself and interrupt it in the circumferential direction, so that the cap-shaped contact surface consists of several cap-shaped contact surface areas separated from each other. The cap-shaped contact surface areas in the circumferential direction are together larger than the circumferential area in which the projections and pockets are arranged.

With the arrangement according to the invention, in which the projections and pockets are arranged directly on the contact surface, the axial length of the pressure piece can be reduced. Only a very limited range of lengths is required to fulfil several functions at the same time. The first function is the transmission of force from the pressure piece to the second tensioning plate via the cap-shaped contact surface areas. No force transmission takes place via the pockets and projections, but only via the cap-shaped contact surface areas or, in short, via the single cap-shaped contact surface.

The second function is anti-rotation. The pockets are arranged in the pressure piece or in the second tensioning plate. Both the pockets and the projections are of such a size that the cap-shaped contact surface areas are completely separated from each other. The axial length of the cap-shaped contact surface is fully utilized for anti-rotation, so that the projections and pockets are not only adjacent in the axial direction to the cap-shaped contact surface areas, but also completely pass through them in the axial direction. The anti-rotation can have relatively small dimensions, since no pressure forces are transmitted through the anti-rotation in the axial direction.

It is emphasized that the cap-shaped contact surface areas are not individual linear contacts, but the cap-shaped contact surface areas are circumferential areas extending to several degrees within a single axial plane, so that the contact between the pressure piece and the tensioning plate has the largest possible surface area, which in turn contributes to uniform force transmission and the avoidance of stress peaks in the components.

The third function that is fulfilled in the area of the contact surfaces is the function of compensating for the angular positions between the pressure piece and the tensioning plate.

From a manufacturing point of view, it is particularly advantageous to arrange the pockets in the pressure piece and to produce the projections in the tension plate. The tension plates are preferably forged components, while the pressure piece is manufactured as a turned or milled part. It is easier to introduce depressions distributed along the contour into the pressure piece than projections, since this would require a greater material removal adjacent to the projections.

In an advantageous development of the invention, it is provided that the pockets are deeper than the projections are high. The projections extend into the pockets. The corresponding specifications on depth and height are to be understood as meaning that when the pressure piece and the second tensioning plate are axially aligned, a gap remains between the surfaces of the pockets and the projections. The gap between the pockets and the projections is substantially larger than necessary for easy mounting. The clearance also exists laterally, i.e. radially, so that a radial tilting of the pressure piece relative to the tensioning plate is possible. The clearance resulting from the gap also exists in the axial direction of the tensioning device, so that the tensioning plate can be tilted to a limited extent relative to the pressure piece by a movement along the cap-shaped contact surface without contact between the projections and the pockets. Tilting is only possible to a limited extent. The opening in the second tensioning plate has a diameter that increases with increasing distance from the cap-shaped contact surface. In particular, the diameter is conically enlarged, for example with an opening angle of 10°-15°. This means that the tensioning plate can be tilted by 5° to 7.5° in any direction. To ensure that contact between a spindle of the tensioning device and the tensioning plate does not occur when the tensioning plate is tilted, the pressure piece can have an axis that runs through the opening over its entire length. The axis encloses the spindle of the tensioning device.

The size and shape of the gap between the shaft and the opening determines how far the tensioning plate can be tilted.

In an advantageous development of the invention, it is provided that the first tensioning plate at the other end of the tensioning device can also be axially coupled to the latter in a pivotable manner. An abutment with a contact surface in the form of a spherical cap can be arranged on the spindle or contact surface areas in the form of a spherical cap can be formed in combination with a rotation-proof device in order to prevent the tensioning plate from rotating relative to the spindle.

It is emphasised that the individual contact surface areas on the pressure piece and on the second tensioning plate form part of the single spherical shell-shaped contact surface. They are therefore not individual small areas, in particular in the form of a spherical shell, with each spherical shell-shaped contact surface having a different centre in the sense of different shell-shaped depressions.

The spherical cap-shaped contact surfaces preferably extend over an angular range of at least 15° each. The angular range relates to the circumferential direction around the longitudinal axis of the tensioning device. Preferably, the individual contact surface areas extend over 20°-40° with 6 contact surface areas. The number of contact surface areas or pockets and depressions is preferably between 2 and 12, in particular between 4 and 12, with particularly preference being given to 6 pockets.

The spherical cap-shaped contact areas between the projections do not necessarily have to be identical in size to the spherical cap-shaped contact surfaces between the pockets. In particular, the spherical cap-shaped contact surface areas between the projections are larger than the spherical cap-shaped contact surface areas between the pockets. The pockets are somewhat wider than the projections, which is to the detriment of the spherical cap-shaped contact surface areas. However, overall the contact surface areas are larger than the areas that are not designed as contact surfaces and are occupied by the pockets and projections.

It is also not necessary for the spherical cap-shaped contact surface areas to have the same length in the axial direction or to extend over an angular area of equal size in the axial direction of the tensioning device or the pressure body. In particular, the contact surface area on the tensioning plate can have a smaller axial length than the contact surface area on the pressure body. The pressure body acts as an inner part (sphere) and the tensioning plate acts as an outer part (spherical shell). The tensioning plate slides over the inner pressure body, so that the inner pressure body is in contact with the tensioning plate in different axial sections depending on the angular position. The pressure body as a smaller component and as a rotating component is easier to machine with regard to the surfaces. Larger spherical cap-shaped contact surface areas can be produced here more easily.

The spring compressor according to the invention has a multifunctional zone in the pressure part, which means that the pressure part can be constructed substantially shorter, more compact and also simpler. It is also cheaper to manufacture and fulfils the same functions as more complex constructions with separate functional zones.

The invention is explained in more detail below on the basis of an exemplary embodiment shown in schematic drawings.

They show:

Figure 1: A spring compressor according to the invention in the installation position;

Figure 2: a longitudinal section along line II-II in Figure 1;

Figure 3: detail III of figure 2;

Figure 4: A spring compressor pressure piece in a side view;

Figure 5: a section along the V-V line in Figure 4;

Figure 6: The pressure piece from Figure 4 in a perspective view;

Figure 7: The pressure piece from Figure 4 in an axial view;

Figure 8: The second tensioning plate of the spring compressor in a side view;

Figure 9: The tensioning plate from Figure 8 in a perspective view from its outer side;

Figure 10: The tensioning plate from Figure 8 in an axial view from its outer side;

Figure 11: a section along the line XI-XI of Figure 10 and an enlarged representation of partial area A;

Figure 12: a view of the support surface of the tensioning plate of Figure 8 in the axial direction;

Figure 13: A side view of the spring compressor with the second tensioning plate, partially in section, in case of axial alignment and

Figure 14: The spring compressor according to Figure 13 in an inclined position of the second tensioning plate with respect to the tensioning device.

1 and 2 show a side view and a longitudinal section of a spring compressor 1 which is inserted into a helical compression spring 2. The spring compressor 1 comprises a tensioning device 3 and a first and a second tensioning plate 4, 5. The first tensioning plate 4 has an opening 6 which is open towards the circumferential side for the attachment of the tensioning device 3. The lower tensioning plate 5 has a central opening 7 into which the tensioning device 3 is inserted. The tensioning plates 4, 5 each have mutually facing support surfaces 8, 9 for the turns of the helical compression spring 2. On the outer surfaces of the tensioning plates 4, 5 opposite the support surfaces 8, 9, the tensioning device 3 has devices for exerting pressure on the tensioning plates 4, 5 to tension the helical compression spring 2. For this purpose, in the region of the second tensioning plate 5, the tensioning device 3 is provided with a spring-loaded spring 10. For tensioning 5, a pressure piece 10 is used, which is shown in enlarged cross section in Figure 3.

The pressure piece 10 can be displaced in the longitudinal direction on a threaded spindle 11 of the tensioning device 3. A tensioning nut 12 is attached to the threaded spindle 11 as an actuator. The pressure piece 10 is supported on the tensioning nut 12 by means of an axial bearing 13 in the tensioning nut 12. When the tensioning nut 12 is turned, the pressure piece 10 is displaced axially. The pressure piece 10 does not rotate with it. It is guided via a slot guide 14. A slot block 16, which is arranged in a groove 15 of the threaded spindle 11 running in the longitudinal direction of the threaded spindle 11, is engaged with an axis 17 of the pressure piece 10. The axis 17 passes through the opening 7 over its entire axial length. The pressure piece 10 is fixedly held in the slot 15 on the threaded spindle 11 via a stop 18.

4 to 7 show the pressure piece 10 in different representations and 8 to 12 show the second tensioning plates 5. The pressure piece 10 serves to transmit a compressive force to the second tensioning plate 5. The compressive force is transmitted via a spherical cap-shaped contact surface 19, the geometric position of which is shown in FIG. 11 shows a section through the second tensioning plate 5 along the line XI-XI in FIG. 10. FIG. 11 shows the section plane in the left-hand image plane and the detail A in an enlarged scale representation in the right-hand image plane. The spherical cap-shaped contact surface 19 in the region of the second tensioning plate 5 borders on the funnel-shaped widening opening 7. Figure 11 shows that the diameter D1 of the opening 7 in the second tensioning plate 5 increases continuously in the direction towards the support surface 9.

Furthermore, it can be seen from Figures 9 to 11 that the contact surface 19 is completely interrupted several times. On the contact surface 19 there are a total of six projections 20 evenly distributed across the circumference, which rise radially inwards beyond the contact surface 19 in the form of a spherical cap. The contact surface 19 is thus divided into individual contact surface regions 21 of equal size. Figure 10 shows the size ratio of the contact surface regions 21 to the projections 20. The projections 20 are substantially narrower or extend over a smaller circumferential area than the contact surface regions 21. The remaining contact surface 19 is therefore overall larger than the area occupied by the projections 20.

The arrangement of the projections 20 corresponds to the pockets 22 in the pressure piece 10. Figures 4 to 7 show the pressure piece 10 with the mentioned pockets 22. The pressure piece 10 also has a spherical cap-shaped contact surface 23, which corresponds to the contact surface 21 in Figure 11. The circle 25 drawn in Figure 11 defines the position of the spherical cap-shaped contact surface 19. With exact axial alignment of the pressure piece 10 and the second tensioning plate 5, the center 26 of the circle 25 drawn in Figure 11 is also located in the center of the contact surface 23 of a pressure piece 10 arranged there. The circle 25 is, of course, only the cross section through the spherical cap-shaped surface.

Figure 4 shows that the contact surface 23 is divided by the pockets 22 into contact surface areas 24 arranged at a distance from each other. In contrast to the contact surface areas 21 on the tensioning plate 5, the contact surface areas 24 on the pressure piece 10 are somewhat shorter when viewed in the circumferential direction (Figure 7). The contact surface areas 24 are somewhat longer in the axial direction of the pressure piece 10 than the contact surface areas 21 on the tensioning plate 5. The contact surface areas 24 border the shaft 17 of reduced diameter in the axial direction. An opening 27 is arranged in the shaft 17 for receiving the collet block 16. This is a radial hole.

The contact surfaces 24 and the pockets 22 are located on or within a circumferential collar at the transition to a substantially cylindrical base body 28, which is larger than the axis 17. The compression force is transmitted from the tensioning nut 12 to the contact surface regions 24 via the base body 28. The base body 28 itself accommodates an axis section of the tensioning nut 12 (FIG. 3). The pressure body 10 is guided in this way.

Figure 7 shows in an axial view from the direction of the axis 17, which has a thinner diameter, that the pockets 22 occupy approximately half of the entire circumferential area, the remaining circumferential area corresponding to the contact surface areas 24. The pockets 22 are wider than the projections 19, so that the lower tensioning plate 5 can be displaced relative to the pressure piece 10 without stresses being formed in the axial direction in the area of the pockets 22 or in the area of the projections 20 due to contact with each other.

Figure 3 shows the application of the projections 20 in the pockets 22. It can be seen that in the axial alignment shown there is no contact between the projections 20 and the pockets 22. The contact surface areas of both components are located outside the cutting plane of Figures 2 and 3, but there they touch each other.

It is important that the pockets 22 not only have sufficient depth, but also sufficient length. If, for example, the tensioning plate 5 is tilted clockwise to the right in the image plane in FIG. 3, the left-hand projection 20 in the image plane within the pocket 22 could move freely upwards, while the right-hand projection 20 in the image plane is likewise displaced downwards within the other pocket 22. The movement ends when the conical inner wall 29 of the opening 7 comes into contact with the outer side 30 of the shaft 17.

In the case of such a displacement, no compression occurs between the projections 20 and the pockets 22. The condition for this is that the pockets 22 extend sufficiently in the axial direction, which is the case in the invention because the contact surfaces are completely interrupted. However, the exemplary displacement in a clockwise direction also leads to the projections arranged perpendicular to the section plane shown in FIG. 3 being positioned obliquely to the longitudinal axis of the pressure piece 10. In order to avoid a collision with the pockets 22, the pockets 22 must also have a certain minimum width in the circumferential direction. FIGS. 13 and 14 show another section plane through the spring compressor 1 mentioned. The spring compressor 1 and the second tensioning plate 5 are exactly aligned in the axial direction with respect to the longitudinal axis LA1 of the tensioning device 3 in Figure 13. The contact surfaces 19, 23 of the second tensioning plate 5 and the pressure piece 10 lie against each other. The projections and grooves are not visible in this sectional plane.

Figure 14 shows a situation in which the longitudinal axis LA1 of the tensioning device 3 deviates by an angle of 5° from the longitudinal axis LA2 of the opening 7 in the second tensioning plate 5. The axis 17 is offset to the left in the image plane and abuts the inner wall 29 of the opening 7 on the left side of the image plane and a gap 31 in the opening 7 is asymmetrical. The end of the tilting movement has been reached. In this position there is no contact between the pockets and the projections. The pressure piece 10 serves for pressure transmission and angle compensation. Only when the second tensioning plate 5 is rotated about the longitudinal axis LA1 or LA2 of the spring compressor or the opening 7 do the projections 20 come into contact with the walls of the pockets 22, viewed in the circumferential direction. The projections 20 and pockets 22 are therefore not intended for the transmission of a compressive force directed in the axial direction, but exclusively as a protection against rotation.

Reference symbols

1 - spring compressor

2 - helical compression spring

3 - tension apparatus

4 - first tensioning plate

5 - second tensioning plate

6 - 4 opening

7 - opening in 5

8 - support surface for 2

9 - support surface for 2

10 - 3-piece pressure piece

11 - threaded spindle

12 - clamping nut

13 - axial bearing

14 - Colisa guide

15 - nut

16 - Colisa block

17 - 10 axis

18 - stop

19 - contact surface

20 - outgoing on 19

21 - contact surface area of 19

22 - pocket in 10

23 - contact surface of 10

24 - contact surface area of 23

25 - circle of 19

26 - center of 25

27 - opening in 17

28 - 10 base body

29 - 7 interior wall

30 - outer side of 17

- gap between 29 and 30

D1 - diameter of 7

LA1 - longitudinal axis of 1

LA2- longitudinal axis of 7

W- angle

Claims (9)

1. Spring compressor (1) with a tensioning device (3) which can be axially inserted into a helical spring (2) to be tensioned, and with a first and a second tensioning plate (5) which can be coupled to the tensioning device (3) at a distance from each other, the second tensioning plate (5) having an opening (7) for receiving the tensioning device (3), in which a pressure piece (10) can be displaced along the tensioning device (3) by the action of an actuator to adjust the distance between the tensioning plates (4, 5), a cap-shaped contact surface (19) being formed between the pressure piece (10) and the second tensioning plate (5) for the transmission of force as well as a rotation-proof locking device to prevent the pressure piece (10) from rotating relative to the tensioning plate (5), the rotation-proof locking device having projections (20) and pockets (22) for the projections (20), characterized in that the projections (20) and the pockets (22) interrupt the cap-shaped contact surface (19) in the circumferential direction and divide it into contact surface areas (21, 24) separated from each other, the cap-shaped contact surface areas (21) in the circumferential direction being as a whole larger than the circumferential area in which the projections (20) and the pockets (22) are arranged. 2. Spring compressor according to claim 1, characterized in that the pockets (22) are made in the pressure piece (10) and the projections (20) in the tensioning plate (5). 3. Spring compressor according to claim 1 or 2, characterized in that the pockets (22) are deeper than the projections (22) are high, so that the tensioning plate (5) can be tilted to a limited extent relative to the pressure piece (10) by a movement along the cap-shaped contact surface (23) without contact between the projections (20) and the pockets (22). 4. Spring compressor according to one of claims 1 to 3, characterized in that an opening (7) for receiving the tensioning apparatus (3) is arranged in the second tensioning plate (5), the opening (7) having a diameter (D1) which increases with increasing distance from the cap-shaped contact surface (19). 5. Spring compressor according to one of claims 1 to 4, characterized in that the first tensioning plate (4) can be axially coupled to the tensioning apparatus (3) so that it can be tilted relative to the tensioning apparatus (3). 6. Spring compressor according to one of claims 1 to 5, characterized in that the contact surface regions (21, 24) are parts of the single contact surface (23) in the form of a spherical cap. 7. Spring compressor according to one of claims 1 to 6, characterized in that each of the contact surface regions (21, 24) in the form of a spherical cap extends through an angular range of at least 15° with respect to the longitudinal axis (LA1) of the tensioning apparatus (3). 8. Spring compressor according to one of claims 1 to 7, characterized in that the spherical cap-shaped contact surface areas (21) between the projections (20) are larger than the spherical cap-shaped contact surface areas (24) between the pockets (22). 9. Spring compressor according to one of claims 1 to 8, characterized in that the spherical cap-shaped contact surface areas (24) on the pressure body (10) extend over a larger angular range with respect to a transverse axis of the tensioning device (3) than the spherical cap-shaped contact surface areas (21) on the tensioning plate (5).